KR101711897B1 - Method for removing foreign substances in charged particle beam device, and charged particle beam device - Google Patents

Abstract

When an ordinary electric field is applied to an electrode disposed in the vicinity of the magnetic field and the objective lens in a case where it is normally used for the objective lens, foreign substances existing in the sample chamber are attached to or attracted to the electrode arranged around the objective lens and the objective lens . The stage is moved so that the center of the optical axis is located just above a stand capable of applying a voltage and the potential difference between the electrode arranged in the vicinity of the objective lens and the electrode arranged in the periphery of the stage is changed periodically To the minimum and the minimum, so that it is forcibly dropped to a voltage-capable dedicated stand.

Description

TECHNICAL FIELD The present invention relates to a method for removing foreign matter in a charged particle beam apparatus and a charged particle beam apparatus using the charged particle beam apparatus,

The present invention relates to a charged particle beam apparatus for irradiating a charged particle beam onto a sample, and more particularly, to a foreign particle removing method and a charged particle beam apparatus in a charged particle beam apparatus capable of removing foreign substances present in a vacuum chamber.

A charged particle beam apparatus typified by a CD-SEM (Critical Dimension Scanning Electron Microscope) for semiconductor wafer measurement is a charged particle beam apparatus that generates an image based on signals (secondary electrons and reflected electrons) obtained by scanning a charged particle beam on a sample . There is a semiconductor device as an object to be inspected and measured by CD-SEM.

Semiconductor devices are being miniaturized to improve device performance and circuit performance. The demand for a killer foreign substance allowed in a semiconductor device becomes more severe due to the miniaturization of the semiconductor device. Examples of specific foreign substances include contamination by outgas of the semiconductor device itself, micro-foreign matter brought in by the semiconductor device, and oscillation from the CD-SEM sliding portion.

The foreign substances are suspended in a sample chamber of a vacuum, or attached to a stage, an objective lens, a sample chamber wall, or the like. If a foreign object attaches to a semiconductor device under measurement, the yield may be lowered and management is required. At present, foreign matter is measured on a regular basis, and when it is out of specification, foreign matters are removed by cleaning the generated portion with ethanol.

On the other hand, Patent Document 1 discloses a technique in which, when the sample is released from the lower portion of the objective lens for focusing an electron beam, the excitation of the objective lens is turned off or low excited, or the electron beam is accelerated A method of effectively removing foreign matter while suppressing the adhesion of foreign matter to the sample is disclosed by setting the applied voltage of the acceleration cylinder to Off or a low voltage.

Japanese Patent No. 4945267 (corresponding to U.S. Patent No. 7,626,166)

Although the ethanol cleaning can remove the foreign substance, it is necessary to release the sample chamber to the atmosphere. Even if the vacuum exhaust is performed after cleaning, the foreign substances entering at the time of the atmosphere release are attached again to the stage, the objective lens, the sample chamber wall, There is a possibility to float in the thread. In addition, it is not realistic to clean ethanol frequently because it causes downtime of several hours by atmospheric liberation and vacuum furnace.

In the method described in Patent Document 1, in which the excitation of the objective lens is set to Off or low excitation, or the applied voltage of the acceleration cylinder for accelerating the electron beam when passing through the objective lens is set to Off or a low voltage, After weakening the force attached to the cylinder, it is free fall by gravity. Therefore, only when the attraction force is larger than the force to which the foreign matter is attached, the foreign matter falls, and foreign matters with high adhesion force may not be sufficiently removed.

Specifically, even if the excitation of the objective lens is turned off or low excitation, even if the influence of the hysteresis remains and the voltage applied to the acceleration cylinder is set to Off or a low voltage, the effect of the Coulomb force acting between the foreign matter and the acceleration cylinder remains. It may be continuously attached. If such a foreign matter accumulates and becomes a large mass, even if the objective lens is excited, it falls due to gravity. However, it is difficult to grasp the dropping time, and it is desired to remove it quickly before the foreign matter accumulates.

A foreign matter removal method and a charged particle beam device in a charged particle beam device for the purpose of rapidly removing foreign matter having a large attraction force even without falling or scattering on a sample will be described below.

According to one aspect of the present invention, there is provided an objective lens system comprising an objective lens for focusing a charged particle beam emitted from a charged particle source, a control device for controlling a lens intensity of the objective lens, And a foreign substance collecting member for collecting foreign substances in a vacuum chamber, wherein the foreign substance collecting member is positioned below the beam passing opening of the objective lens And the stage is moved so that the foreign matter collecting member is positioned under the beam passing opening of the objective lens, the foreign matter collecting member and the objective lens, or the stage and the objective lens, So that a potential difference is generated between the foreign matter collecting member and the stage And an electrode for generating a potential difference between the objective lens and the objective lens, and / or a charged particle beam device for applying a voltage to the magnetic pole.

In another aspect of the present invention, there is provided a method for removing foreign matter in a charged particle beam apparatus for removing foreign matter in a vacuum chamber of a charged particle beam apparatus, comprising the steps of: A stage for placing the foreign matter collecting member or the sample is moved so that the foreign matter collecting member for collecting is positioned, and in a state where the foreign matter collecting member is positioned below the beam passing opening of the objective lens, A method for removing foreign matter in a charged particle beam apparatus which forms a potential difference between a member or a stage and the objective lens is proposed.

According to the above configuration, since the foreign matter can be removed from the objective lens or the like in a state where the foreign matter collecting member is positioned under the beam passing opening of the objective lens, the possibility of attachment of the foreign matter to the sample or diffusion of the foreign matter in the vacuum chamber can be suppressed It is possible to recover the foreign matter.

Other objects, features and advantages of the present invention will become apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a scanning electron microscope. Fig.
2 is a flow chart showing the process of collecting and recovering foreign matter.
3 is a view showing a sample stage having a foreign matter collecting member;
4 is a diagram showing an outline of a foreign matter collecting member;
5A is a view showing the movement of foreign matter in the foreign matter collecting step and the foreign matter collecting step.
FIG. 5B is a diagram showing the movement of foreign matter in the foreign matter collecting process and the foreign substance collecting process. FIG.
FIG. 5c is a view showing the movement of foreign matter in the foreign matter collecting process and the foreign substance collecting process; FIG.
6 is a diagram showing a circuit configuration including a power source for generating a potential difference between a foreign matter collecting member and an objective lens;
7 is a schematic view of a scanning electron microscope having an electrode for controlling an electric field on a sample.
8 is a view showing an example of an acceleration passing objective lens for accelerating a beam.
9 is a view showing an example of an objective lens in which a part of magnetic poles is used as an accelerator for accelerating a beam.
10 is a schematic view of a scanning electron microscope having a foreign substance collecting member at the bottom of a sample chamber.
11 is a view showing an example in which a foreign matter collecting member is mounted on a sample stage;
12 is a flowchart showing a process of recovering a foreign substance by introducing a foreign substance collecting member into the sample chamber.
13 is a time chart showing a time change of a voltage applied to electrodes around the sample.

Hereinafter, a scanning electron microscope having a foreign matter collecting member will be described. In this embodiment, in particular, before the foreign object is collected, an electric field is generated when the electrode arranged around the objective lens is used normally so as to generate a magnetic field higher than that when the objective lens is used normally, An excitation current, and / or an applied voltage are controlled so as to be larger than the value of the excitation voltage. By forming a magnetic field and an electric field larger than those used as the electron microscope, the foreign substances existing in the sample chamber can be attached to or attracted to the electrodes arranged around the objective lens and the objective lens. A foreign matter attracted to or attached to the periphery of the stage is forcedly dropped to a foreign matter collecting member provided in the vicinity of the sample stage by forming a potential difference between the electrode arranged around the objective lens or the objective lens and the electrode arranged around the stage, It is possible to remove foreign matter while suppressing the possibility of attachment to the sample or scattering of foreign matter. At this time, by setting the potential difference periodically to the maximum and minimum, it is possible to promote the escape of foreign matter adhered to the objective lens and the like, and to improve the recovery efficiency.

In this embodiment, as described above, an example in which the foreign substance attracted once around the objective lens is recovered by an electric field and / or a magnetic field is mainly described. However, when the adhesion of the foreign matter is remarkable, Just as good as it is.

With this arrangement, it is possible to positively collect foreign substances in the sample chamber without collecting the sample chamber in the air, and to collect the collected foreign substances with high efficiency.

1 is a schematic configuration diagram of a scanning electron microscope according to the present invention. The electron beam 103 drawn by the drawing electrode 102 from the electron source 101 and accelerated by an accelerating electrode (not shown) is narrowed by the condenser lens 104, which is one type of focusing lens, And is scanned one-dimensionally or two-dimensionally on the sample 109 by the deflector 105. The electron beam 103 is decelerated by the negative voltage applied to the electrode built in the sample stage 108 and focused by the lens action of the objective lens 106 to be irradiated onto the sample 109.

When the electron beam 103 is irradiated onto the sample 109, electrons 110 such as secondary electrons and back scattered electrons are emitted from the irradiation spot. The emitted electrons 110 are accelerated in the direction of the electron source by the accelerating action based on the negative voltage applied to the sample and collide with the converting electrode 112 to generate the secondary electrons 111. [ The secondary electrons 111 emitted from the conversion electrode 112 are captured by the detector 113 and the output of the detector 113 is changed by the amount of captured secondary electrons. According to this output, the luminance of a display device (not shown) changes. For example, in the case of forming a two-dimensional image, an image of the scan area is formed by synchronizing the deflection signal to the scanning deflector 105 and the output from the detector 113. [

In addition to the deflection signal for performing two-dimensional scanning in the field of view, a deflection signal for moving the field of view may be superimposed on the scanning deflector 105 in some cases. This deflection by the deflection signal is also referred to as an image shift deflection, and it is possible to move the field of view of the electron microscope without moving the sample by the sample stage. In the present embodiment, the image shift deflection and the scanning deflection are performed by a common deflector, but a deflector for image shift and a deflector for main use may be separately provided.

In the example of Fig. 1, an example in which the electrons emitted from the sample are once converted and detected by the converting electrode is described. However, the present invention is not limited to such an arrangement. For example, It is also possible to arrange a detection surface of the correlation or detector.

The control device 120 controls each configuration of the scanning electron microscope and has a function of forming an image based on the detected electrons and a function of forming a pattern formed on the sample based on the intensity distribution of the detection electrons, And a function of measuring the pattern width of the pattern.

The scanning electron microscope illustrated in FIG. 1 also includes a preliminary evacuation chamber 115 for preliminarily evacuating the sample atmosphere and a minien 117 for forming an air clean space when the sample is introduced into the sample chamber 107 Is installed. Vacuum valves 114 and 116 for vacuum sealing are provided between the spaces.

Positive or negative voltage is applied to the electric field forming electrode 118 by an instruction from the control device 120, and the surface electric field of the sample 109 is controlled. Usually, the electric field forming electrode 118 is used to form an electric field for attracting electrons emitted from the sample 109 toward the electron source 101, or to form an electric field for deflecting electrons having low energy. On the sample stage 108, a foreign matter collecting member 119 is provided. As shown in Fig. 3, the foreign matter collecting member 119 is provided at a position other than the position where the sample 109 of the sample stage 108 is mounted.

A method of recovering foreign matters in a scanning electron microscope having the above-described structure will be described below. In addition, the following embodiments are described by taking a scanning electron microscope as an example, but the present invention is not limited thereto, and it is also possible to apply the present invention to the recovery of foreign substances from other charged particle beam devices such as a focused ion beam using an ion beam as a probe.

2 is a flowchart showing a process of collecting and recovering foreign matter. First, the sample 109 is taken out from the sample chamber 107 and the vacuum valve 114 is closed (steps S201 and S202). Next, by applying an electric field equal to or larger than that required when forming a magnetic field more than that normally used for an objective lens and / or when using an electrode disposed around the objective lens, the foreign substances existing in the sample chamber are arranged around the objective lens and the objective lens Attached to electrodes or pulled around them (step S203). The electric field for collecting the foreign substance applies a large voltage to the electric field forming electrode 118, for example, as compared with the case where it is used as an electron microscope. In the case of using an apparatus as an electron microscope, the excitation current or the like of the objective lens is controlled so as to narrow the beam finely. However, in this example, since a magnetic field or the like is generated for the purpose of collecting foreign substances, A higher electric field or a magnetic field is formed compared with the case where the device is used as an electron microscope. That is, as compared with the case of irradiating a beam, it is possible to increase the collection efficiency of foreign matter by applying a large voltage or supplying a large current.

5A and 5B are diagrams showing positions of the foreign matter 501 before and after collection of the foreign matter by forming a strong electric field or the like. As shown in the drawing, when a high voltage is applied to the strong excitation of the objective lens 106 or the electric field forming electrode 118, the foreign matter 501 collects foreign substances in the objective lens 106 and the electric field forming electrode 118 I will. In order to completely remove the metal-based foreign matter and the electrode disposed around the objective lens, the charged object and the non-conductive foreign substance are attracted to the objective lens. It is preferable to perform the application of the strong voltage.

After the foreign object is attached or pulled to the periphery, the stage is moved so that the center of the optical axis is located just above the voltage-capable dedicated unit (step S204). In this case, the sample stage 108 is moved so that the foreign matter collecting member 119 is positioned just below the passing opening through which the electron beam of the objective lens with the most foreign substance passes. Next, in a state in which the foreign matter collecting member 119 is positioned below the beam passage opening of the objective lens 106, the magnetic field of the objective lens 109 is set to Off or relatively weak, An electric field is formed by applying a voltage to one electrode, and the foreign matter is forcefully dropped to the foreign matter collecting member 119. 5C is a diagram showing a state in which the foreign matter falls on the foreign matter collecting member 119 by electric field control.

In the present embodiment, the magnetic field of the objective lens is turned off, and the potential difference between the electrode disposed in the periphery of the objective lens and the electrode disposed in the periphery of the stage is periodically maximized and minimized, . The purpose of cutting off the magnetic field of the objective lens is to prevent the foreign matter from adhering to the objective lens while weakening the force to attach the foreign matter to the objective lens.

It is also possible to generate a potential difference with a positive voltage or a voltage when generating a potential difference between the electrode arranged around the objective lens and the electrode arranged around the stage. For example, when the voltage of the electrode arranged around the objective lens is 5 kV and the voltage of the electrode arranged around the stage is 0 kV, the potential difference becomes 5 kV. When the voltage of the electrode arranged around the objective lens is 5 kV and the voltage of the electrode arranged around the stage is -5 kV, the potential difference becomes 10 kV. When the voltage of the electrode arranged around the objective lens is 0 kV and the voltage of the electrode arranged around the stage is -5 kV, the potential difference becomes 5 kV. That is, the potential difference can be generated by various methods. However, it is necessary to provide a large power source in order to generate a high potential difference by only one side. Therefore, it is desirable to generate a higher potential difference with two voltages.

FIG. 13 is a time chart showing a time change of a voltage applied to each electrode at the time of collecting foreign matters. Vb is an applied voltage to the electric field forming electrode 118, and Vr is a voltage applied to the retarding electrode embedded in the sample stage. By controlling the applied voltage such that Vb and Vr are synchronously changed and the potential difference between both electrodes is repeated at the maximum (| Vb | + | Vr |) and minimum (0 V) as shown in Fig. 13, It is possible to further promote the fall of the foreign matter. Vb1 and Vr1 in Fig. 13 are maximum values of the applied voltage in the case of measurement or observation by an electron microscope. By applying a large voltage exceeding the voltage range used in the case of using it as an electron microscope, it is possible to increase the reliability of foreign matter dropping.

6 is a view showing an example of a sample stage in which a retarding electrode 502 to which a retarding voltage is applied is incorporated. The retarding electrode 502 is a form of an electrode disposed around the above-described stage. In the example of Fig. 6, an auxiliary power supply 602 for generating a strong-current system is provided in addition to the normal retarding voltage power supply 601. [ As described above, foreign matter can be forcibly dropped by controlling the voltage applied to the retarding electrode 502. However, since the potential at the center of the sample stage 108 becomes higher in the foreign matter collecting member 119, A dislocation gradient is formed around the slit 119, and there is a possibility that foreign matter falling is deflected. According to the example of Fig. 6, it is possible to eliminate the potential gradient as described above by switching the switch 603 by the control device 120 and by setting the foreign substance collecting member 119 to a high potential at the time of collecting the foreign matter .

The electrode disposed in the vicinity of the objective lens is not limited to the electrode facing the sample and arranged on the electron source side rather than the lens main surface of the objective lens such as the electric field forming electrode 118, It can be substituted by an electrode to be positioned. 7 is a view showing an example in which an electric field forming electrode 702 is formed below the magnetic pole of the objective lens 106. In Fig. Figs. 8 and 9 are views for explaining the installation example of the electric field forming electrode 702 in more detail. 8 is a diagram showing an example in which an acceleration cylinder 801 for accelerating the electron beam is provided inside the beam passage opening of the objective lens 106. In Fig. The electric field control at the time of collecting foreign matter can be performed by controlling the voltage applied to the electric field forming electrode 702 and / or the accelerating cylinder 801. [ 9 shows a structure of an objective lens for accelerating an electron beam by dividing an upper magnetic pole 901 and a lower magnetic pole 902 of the objective lens 106 and selectively applying a high voltage to the upper magnetic pole 901 However, the electric field may be controlled at the time of collecting foreign matter by controlling the voltage applied to the upper magnetic pole 901 and / or the electric field forming electrode 702. In addition, an electrode or the like for controlling the trajectory of the secondary electron may be used as the electric field control electrode at the time of collecting foreign matter.

The electrodes disposed in the vicinity of the stage can be replaced by electrodes other than the retarding electrode 502 and the foreign matter collecting member 119. A concrete example is shown in Fig. 10 shows an example in which an electric field forming electrode 1003 is disposed on the bottom of a vacuum sample chamber 1002 of an electron microscope including an electron beam column 1001 and a vacuum sample chamber 1002. [ However, when the electrode placed on the bottom of the sample chamber is used, the distance from the electrode arranged around the objective lens becomes long, so that a larger voltage is required for forced drop of the foreign substance. As described above, it is also possible to recover foreign substances from the retarding electrode and the electrode placed on the bottom of the sample chamber, but it is necessary to arrange a dedicated stand capable of applying voltage to the upper surface of the electrode to be used.

When the objective lens is used normally, the foreign matter can be attracted to or around the objective lens by generating a magnetic field higher than that of the objective lens. At this time, the higher the magnetic field, the higher the efficiency of attaching or attracting foreign matter, so that it is preferable that a higher magnetic field can be applied to the objective lens.

By generating an electric field equal to or higher than that in the case of using the electrode arranged around the objective lens, the foreign matter can be attached to or attracted to the electrode arranged around the objective lens. At this time, the higher the electric field, the higher the efficiency of attaching or attracting foreign matter, so that it is preferable that a higher electric field can be applied to the electrode disposed in the vicinity of the objective lens.

When attaching or pulling a foreign substance, no voltage is applied to the electrode disposed in the vicinity of the stage. This is because it is impossible to forcibly drop a foreign object onto a dedicated stand capable of applying a voltage even if foreign substances are attached to the electrode disposed in the vicinity of the stage or foreign substances are drawn to the periphery thereof.

It is preferable that a higher potential difference is generated between the electrode disposed in the vicinity of the objective lens and the electrode disposed in the periphery of the stage because the efficiency of forced dropping is higher as the potential difference is higher.

When the foreign matter is forcibly dropped, the foreign matter that has fallen by force may bounce on the upper surface of the voltage-sensitive exclusive band and may float in the sample chamber again. Therefore, if the upper surface of the voltage- This is good. In order to generate a higher potential difference, it is preferable to set the height so as to be closer to the electrode near the objective lens. At this time, it is necessary to design so as not to contact or interfere with the lens system.

In order to prevent foreign matter that has collected in a specially designed vacuum chamber from being floated in the specimen chamber, a thin vacuum grease is applied to the inside of a dedicated vacuum chamber. It is preferable that an electric field and a magnetic field are generated inside. At this time, it is necessary to design so as not to interfere with the primary electrons and the secondary electrons.

4 is a view showing an example of the foreign matter collecting member 119. Fig. The foreign matter collecting member 119 is formed in a container shape, and a small amount of vacuum grease can be accommodated and applied. In addition, a mesh electrode 401 is provided inside, and a voltage for controlling the electric field at the time of collecting the foreign substances can be applied.

The foreign matter may be recovered by using a bare wafer on the stage or a foreign matter collecting member capable of being introduced from the outside of the sample chamber, without collecting the foreign matter on a dedicated voltage-applicable stand. 11 is a diagram showing an example in which a foreign matter collecting member 1101 carried from the outside of the sample chamber is mounted on the sample stage 108. Fig. By applying the foreign matter collecting member having a large surface area, it is possible to improve the foreign matter collecting efficiency.

FIG. 12 is a flowchart showing a foreign matter collecting process using the foreign substance collecting member 1101. FIG. First, after the sample is taken out, the vacuum valve 114 is closed (steps S1201 and S1202). Next, the electric field control and / or the magnetic field control for collecting the foreign object on the objective lens is performed (step S1203), the vacuum valve 114 is opened and the foreign matter collecting member 1101 is introduced S1204, S1205). Thereafter, the vacuum valve 114 is closed, and the sample stage 108 is moved so that the foreign matter collecting member 1101 is positioned below the beam passage opening of the objective lens (steps S1206 and S1207). Next, in a state where the foreign matter collecting member 1101 is positioned below the beam passing opening of the objective lens 106, the magnetic field of the objective lens 109 is set to Off or relatively weak, An electric field is formed by applying a voltage to one electrode, and the foreign matter is forcefully dropped to the foreign matter collecting member 1101 (step S1208). Thereafter, the vacuum valve 114 is opened and the foreign matter collecting member 1101 is taken out (steps S1209 and S1210).

By collecting the foreign substance through the process as shown in Fig. 12, it is possible to remove the foreign substance with high efficiency without placing the foreign substance collecting member in the sample chamber.

11, in the state where the foreign matter collecting member 1101 is mounted on the sample stage 108, electric field control for collecting the foreign matter is performed and the movable range of the foreign matter collecting member 1101 is scanned The foreign substance removing process can be performed over a wide range in the sample chamber by moving the sample stage 108. However, conveying the bare wafer or the like for each timing of forced dropping may be a cause of lowering the throughput of the apparatus, and therefore it is preferable to previously provide the foreign material removing member in the sample chamber.

In addition, although it is possible to simply drop the sample to the bottom of the sample chamber without using a foreign substance collecting member or the like, the sample may be floated again in the sample chamber only by forced dropping. .

It is essential that the actual operation of the dust collection does not affect the throughput. Specifically, semiconductor manufacturing lines process a large number of product lots, and therefore, they must be collected without impeding their processing.

A specific example will be described. In the semiconductor manufacturing line where the CD-SEM is installed, the product lot is automatically returned, and the CD-SEM can identify the product lot in the waiting atmosphere. As a result, the dust collecting is performed once after the product lot process only when there is no product lot waiting for treatment. In some semiconductor manufacturing lines, the number of lots to be processed may be small. In such a case, there is a high possibility that a clean atmosphere is maintained in the sample chamber, and it is not necessary to collect dust every processing lot, and therefore it is preferable that a certain threshold value can be set for the timing of dust collection. For example, when one week has elapsed from the previous dust collection, or when the number of product lot treatments exceeds 500 sheets, and there is no product lot in the waiting atmosphere, one dust collection is performed after the product lot treatment. In addition, the device start and restart can be triggered by dust collection.

On the other hand, due to the semiconductor manufacturing process, there is a possibility that a lot of outgas is processed in relation to a process or material that is not cleaned for removing foreign substances. In such a case, it is preferable to perform dust collection every predetermined measurement interval, or collect dust when the degree of vacuum deteriorates.

While the above description has been made with respect to the embodiments, it is apparent to those skilled in the art that the present invention is not limited thereto, and that various changes and modifications can be made within the spirit and scope of the appended claims.

101: Electronic circle
102: lead electrode
103: electron beam
104: condenser lens
105: scanning deflector
106: objective lens
107: sample chamber
108: sample stage
109: Sample
120: Control device

Claims (11)

delete An objective lens for focusing the charged particle beam emitted from the charged particle source,
A control device for controlling the lens intensity of the objective lens,
A vacuum chamber for keeping the atmosphere around the sample to be irradiated with the charged particle beam under vacuum,
And a foreign matter collecting member for collecting foreign matter in a stage or a vacuum chamber on which the sample is placed,
The control device moves the foreign matter collecting member or the stage so that the foreign matter collecting member is positioned under the beam passing opening of the objective lens, and the foreign matter collecting member is positioned below the beam passing opening of the objective lens An electrode for generating a potential difference between the foreign matter collecting member or the stage and the objective lens so that a potential difference is formed between the foreign matter collecting member and the objective lens or between the stage and the objective lens, A voltage is applied to the gate electrode,
Wherein the controller is configured to periodically change a potential difference between the foreign matter collecting member and the objective lens or between the stage and the objective lens in a state where the foreign matter collecting member is positioned below the beam passing opening of the objective lens Wherein the charged particle beam device is a charged particle beam device. 3. The method of claim 2,
The control device controls at least one of an applied voltage to the foreign matter collecting member, an applied voltage to the stage, a voltage applied to the facing electrode facing the sample, or an applied voltage to the accelerating tube for accelerating the charged particle beam Thereby generating the potential difference. 3. The method of claim 2,
Wherein the control device is configured to perform at least one of energization of the objective lens and application of a voltage to an electrode for generating a potential difference between the stage and the objective lens before forming the potential difference, . An objective lens for focusing the charged particle beam emitted from the charged particle source,
A control device for controlling the lens intensity of the objective lens,
A vacuum chamber for keeping the atmosphere around the sample to be irradiated with the charged particle beam under vacuum,
And a foreign matter collecting member for collecting foreign matter in a stage or a vacuum chamber on which the sample is placed,
The control device moves the foreign matter collecting member or the stage so that the foreign matter collecting member is positioned under the beam passing opening of the objective lens, and the foreign matter collecting member is positioned below the beam passing opening of the objective lens An electrode for generating a potential difference between the foreign matter collecting member or the stage and the objective lens so that a potential difference is formed between the foreign matter collecting member and the objective lens or between the stage and the objective lens, A voltage is applied to the gate electrode,
The control device performs at least one of excitation of the objective lens and application of a voltage to an electrode for generating a potential difference between the stage and the objective lens before forming the potential difference,
Wherein the control device excites the objective lens by supplying a large current to the objective lens in comparison with a case where a beam is irradiated onto the sample before forming the potential difference. 5. The method of claim 4,
Wherein the control device is configured to apply a large voltage to at least one of the electrode and the magnetic pole to generate a potential difference between the stage and the objective lens before forming the potential difference as compared with the case of irradiating the sample with the beam, Particle beam device. 3. The method of claim 2,
Wherein the foreign matter collecting member is installed in the stage or in the vacuum chamber. 8. The method of claim 7,
Wherein the foreign matter collecting member is coated with vacuum grease. 8. The method of claim 7,
Wherein the foreign matter collecting member is provided with a mesh-shaped electrode. delete delete

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